STS 51-A Flightcrew Report (no date); Astronautics and Aeronautics, 1979-1984, NASA, 1990, p. 516; "Satellite Retrieval Succeeds Despite Equipment Problem," Aviation Week & Space Technology, November 19, 1984, pp. 16-19; "The Fat Lady Sang," Space News Roundup, NASA JSC, December 7, 1984, p. 2; "Satellite Rescue Made Possible By Detailed Contingency Plans," Craig Covault, Aviation Week & Space Technology, December 10, 1984, pp. 46-49.
Purpose: Perform first unscheduled EVA; install improvised switch-pulling appendages on RMS
One of Discovery's two satellite payloads on mission STS 51-D, the Hughes Syncom-IV/Leasat 3 geosynchronous communications satellite, remained inert after deployment on April 13 and engineers quickly determined that a likely culprit was a faulty switch on the satellite's side. The spate of malfunctions in Shuttle-launched satellites encouraged managers to authorize the first unscheduled EVA of the Shuttle program. Engineers first proposed that an astronaut ride the RMS close to the satellite and trip the switch by hand using an improvised tool. Discovery carried no MFR, however, and astronauts Sherwood Spring and Jerry Ross, working in the WETF, were unable to develop a satisfactory substitute based on materials aboard Discovery. Engineers then hatched a plan in which the EVA astronauts would attach improvised switch-pulling appendages to the RMS end effector. Rhea Seddon would maneuver the RMS so that the appendages snag the switch that started an automatic timer, and Discovery would quickly move away to get clear of the plume from the satellite's kick motor. Griggs and Hoffman trained for contingency EVAs on the canceled STS 41-F and 51-E missions before they were assigned to STS 51-D, so they each had over 50 hr of contingency EVA training - more than four times as much as normal - going into this EVA. EVA operations and in-flight maintenance engineers developed and designed procedures. Ross and Spring simulated the procedure in the WETF, then talked through the planned EVA procedure with Griggs and Hoffman over the radio. The astronauts discussed the procedures between themselves. Two different switch-pullers (the "lacrosse stick" and the "flyswatter") were manufactured using materials on board Discovery, including tape and plastic book covers. Twenty-four hr ahead of the EVA the crew reduced Discovery's cabin pressure to 70.3 kpascal (10.2 psi) to cut prebreathe time to 1 hr. Hoffman called prebreathing "a miserable experience." The thrill of an unexpected trip into Discovery's payload bay quickly overshadowed his discomfort, however. According to his taped diary:
Going out of the airlock... was very much like the water tank because we tended to be looking down, not so much aware of the world going by. It was when I went up to the sill [where the payload bay doors are attached] to start moving back to the work position that I really turned myself upside-down and looked at the Earth going by. That's when the true awesomeness of what we were doing really struck me. That and having an almost 180-degree panorama of the entire world, our spaceship, and me just floating there... there was a part of me just standing back not believing what I was seeing and what I was doing.
Before the EVA Seddon bent the RMS at elbow and wrist to bring the RMS end effector closer to the airlock. The astronauts moved to the end effector, which is about halfway down the payload bay on the starboard side, and attached the switch-pullers with a payload retention strap while EVA CapCom Jerry Ross advised. Griggs and Hoffman rested while they were out of communication range. During night passes both men became cold, as Hoffman describes in his diary:
- ... Sitting around at night I turned the cooling down all the way to keep it as warm as possible. My body was quite comfortable but the tips of my fingers got quite cold. Dave's apparently got even colder.
Their work completed, Griggs pushed himself over the starboard payload bay sill toward the orbiter's delicate radiator panels, and Commander Karol Bobko warned him to return to the payload bay. The astronauts then returned to the warmth of Discovery's crew compartment. Rhea Seddon snared the switch repeatedly with the switch-pullers, but Syncom IV/Leasat 3 remained inert.
August 27
STS 51-D Flightcrew Report (no date); An Astronaut's Diary, Jeffrey Hoffman, 1986, pp. 30-33; "Shuttle 51 D Mission Report," John Pfannerstill, Spaceflight, November 1985, pp. 414-419; email from Charles Walker, September 10, 1996; interview, David S. F. Portree with Jeff Hoffman, June 18, 1996.
April 19
STS-51D/Discovery landing
April 29–May 6
STS-51B/Challenger
June 6
Salyut 7/Soyuz-T 13 PE-4 launch
June 17–24
STS-51G/Discovery
July 29–August 6
STS-51F/Challenger
August 2
1985 EVA 2
World EVA 63 Russian EVA 16 Space Station EVA 24
Duration: 5:00 Spacecraft/mission: Salyut 7 PE-4 Crew: Vladimir Dzhanibekov, Viktor Savinykh Spacewalkers: Vladimir Dzhanibekov, Viktor Savinykh Purpose: Augment Salyut 7 solar arrays; test Orlan-DM suits
This EVA marked the first use of the Orlan-DM space suit designed for deployment on the Mir space station. Orlan-DM featured many improvements over the Orlan-D, including bright lights at the temples of the "headset" for illuminating suit control dials; improved controls; sturdier construction, including rubberized fabric shoulder belts in place of the Orlan-D's rubber belts; and greater mobility. The suits reached Salyut 7 aboard Cosmos 1669 (July 21, 1985), a prototype Progress freighter improved for Mir. During this EVA, Savinykh and Dzhanibekov augmented the port side solar array using two extension panels delivered by Progress 24 (docked June 23, 1985). One extension had an experimental design. This completed the series of solar array augmentation spacewalks planned at Salyut 7's launch to occur over the station's occupancy. Moscow TV showed portions of the EVA live. The cosmonauts used the Orlan-DM's headset lights to continue work during orbital night. They left a small piece of solar cell material outside as an exposure experiment. Before closing out the EVA, they installed a Soviet/French experiment for collecting meteoritic dust (it was expected to gather dust from Halley's Comet) and changed space exposure cassettes near the transfer compartment hatch.
Izvestiya, August 4, 1985, p. 1 (translated in USSR Report: Space, JPRS-USP-86-001, January 13, 1986, pp. 16-17); "Salyut Mission Report," Spaceflight, Neville Kidger, December 1985; Pravda, August 3, 1985, p. 3 (translated in USSR Report: Space, JPRS-USP-86-001, January 13, 1986, p. 18); Izvestiya, August 4, 1985, p. 2 (translated in USSR Report: Space, JPRS-USP-86-001, January 13, 1986, p. 2).
STS-51I/Discovery launch
August 31
1985 EVA 3
World EVA 64 U.S. EVA 48 Shuttle EVA 10
Duration: 7:20 Spacecraft/mission: STS 51-I Crew: Joe Engle, Richard Covey, James van Hoften, William Fisher, John Lounge Spacewalkers: William Fisher, James van Hoften Purpose: Retrieve Leasat 3 satellite; begin repairs
Failure of Syncom-IV/Leasat 3 on STS 51-D in April was followed by four months of intense preparation for a repair EVA. Only a single EVA was planned, but shortly after Discovery reached orbit on August 27 RMS operator Mike Lounge discovered that fuses had blown in the arm, forcing him to position its joints one at a time with no computer assistance. On August 28 mission controllers in Houston determined that two EVAs were necessary to complete the repair and began replanning the mission. Van Hoften and Fisher checked out their suits on August 30. On this date, Discovery made rendezvous with the satellite in a 400-by-290-km (250-by-180-mi) orbit. The astronauts entered Discovery's payload bay and Van Hoften placed his feet in the MFR. The 6818-kg (15,000-lb) drum-shaped satellite rotated very slowly, so Van Hoften found it easy to install a bar for slowing rotation by hand. However, the EVA fell behind schedule because the handling bar - which included a grapple fixture for the RMS end-effector - did not fit at first. The crew complained of being too cold. Van Hoften and Fisher safed the satellite using plugs and specialized tools, then installed a bypass cable harness to work around the faulty switches that prevented activation in April. They discovered that the satellite's batteries had not frozen as some had feared. Syncom-IV/Leasat 3's omnidirectional antenna popped up, indicating a successful repair, and Van Hoften and Fisher closed out the first EVA. The crew left Leasat 3 safed on the RMS when they bedded down for the night.
Ox's Crew Report (no date); Flight 51I Mission Report of Leasat EVA Activities, Crew Systems Division, October 8, 1985; "Shuttle 51-I Mission Report," Roelof Schuiling, Spaceflight, December 1985, pp. 466-468; "Astronauts Repair, Deploy Leasat During Two Space Shuttle EVAs," Craig Covault, Aviation Week & Space Technology, September 9, 1985, pp. 21-23.
September 1
1985 EVA 4
World EVA 65 U.S. EVA 49 Shuttle EVA 11
Duration: 4:26 Spacecraft/mission: STS 51-I Crew: Joe Engle, Richard Covey, James van Hoften, William Fisher, John Lounge Spacewalkers: William Fisher, James van Hoften Purpose: Complete repair of Leasat 3 satellite, release
Van Hoften and Fisher installed an instrumented cover over Syncom-IV/Leasat 3's apogee kick motor nozzle, then armed the motor. The astronauts experienced difficulties handling the satellite, which threatened to collide with Discovery. This was largely because they could not see each other from their positions on opposite sides of the 4.3 m-dia (14 ft-dia) satellite and thus imparted opposing motions. Van Hoften warned that "if something happens and I'm about to lose it, I'm going to give it a heck of a push and bail out." The astronauts managed to control the satellite's motions, however. Van Hoften spun up Syncom-IV/Leasat 3 manually to 3 rpm and released it. In their postflight debrief, the astronauts recommended against EVAs on consecutive days, and stated that the EMU is "unquestionably overcooled." In his crew report, Van Hoften stated that his fingers became very cold while he held Leasat 3, even with water to his LCVG shut off. With the water off, his EMU helmet fogged up. Syncom-IV/Leasat 3 proceeded successfully to geosynchronous orbit after warming up in low-Earth orbit for several months.
Ox's Crew Report (no date); "STS 51-I Mission Report," Roelof Schuiling, Spaceflight, December 1985, p. 468; "Astronauts Repair, Deploy Leasat During Two Space Shuttle EVAs" Craig Covault, Aviation Week & Space Technology, September 9, 1985, pp. 21-23.
September 3
STS-51I/Discovery landing
September 17
Salyut 7/Soyuz-T 14 PE-5 launch
September 26
Salyut 7/Soyuz-T 13 PE-4 landing
October 3–7
STS-51J/Atlantis
October 30–November 6
STS-61A/Challenger
November 21
Salyut 7/Soyuz-T 14 PE-5 landing
November 26
STS-61B/Atlantis launch
November 29
1985 EVA 5
World EVA 66 U.S. EVA 50 Shuttle EVA 12
Duration: 5:32 Spacecraft/mission: STS 61-B Crew: Brewster Shaw, Bryan O'Connor, Sherwood Spring, Mary Cleave, Jerry Ross, Charles Walker, Rodolfo Neri Vela Spacewalkers: Jerry Ross, Sherwood Spring Purpose: Assemble experimental erectable truss structures
The STS 61-B EVAs were designed to demonstrate assembly techniques which might be used in space station assembly. This first EVA focused on human performance. The assembly procedures were precisely timed ahead of the EVAs in NASA neutral buoyancy facilities to determine if underwater simulation verifies EVA performance. In addition, the EMUs were instrumented to allow precise monitoring of oxygen consumption during work. The astronauts first assembled the 3.4-m (11-ft) Assembly Concept for Construction of Erectable Space Structures (ACCESS) assembly jig in Atlantis' payload bay. Each cell was assembled in the jig, then pushed up so that the next cell could be assembled. Ross later called this "a neat way to build a truss." Assembling the ACCESS truss required 58 min in the water tank, and the EVA timeline allotted 2 hr for a single ACCESS assembly. Only 55 min were required to build the truss, however, so the astronauts disassembled it and built it again. The Experimental Assembly of Structures through EVA (EASE) task assessed the capabilities of free-floating astronauts, and involved putting together beams weighing 29 kg (64 lb) to make a 3.6-m (12-ft) three-sided pyramid. EASE was scheduled to be assembled six times, but the astronauts managed eight assemblies. During the first four assemblies the astronauts used foot restraints. Spring noted in his postflight debriefing that his fingers grew numb during the third EASE assembly and very tired during the fourth. At the end of the EVA Spring assembled and hand-deployed a small target satellite to be used after the EVA as a station-keeping target for Atlantis, which played the role of an automated orbital maneuvering vehicle in rendezvous software tests.